On April 26, 2016, in the presidential primaries, voters selected the Democratic, Republican, and Green parties' respective nominees for president. Pennsylvania is a closed primary state, meaning voters must have been previously registered with a particular political party in order to vote for one of that parties' candidates, to participate in their respective party primary.[1]

The Republican party candidate was businessman and former host of The Apprentice (an American reality television program), Donald Trump, who won Pennsylvania by 44,292 votes out of more than six million cast, a difference of 0.72% and the narrowest margin in a presidential election for the state in 176 years, since 1840 when William Henry Harrison defeated Martin Van Buren by just 0.12%.

Prior to the election, Pennsylvania was expected to be close as polling showed the results within the margin of error. However, most election experts viewed Pennsylvania as solidly Clinton.[2][3] On Election Day, Pennsylvania swung to Donald Trump. Trump carried 56 of the state's 67 counties, predominantly rural or semi-rural counties, while Clinton carried much of the Philadelphia metropolitan area as well as other cities including Pittsburgh, Harrisburg and Scranton. Nonetheless, some areas of traditional Democratic strength such as Luzerne County, where Wilkes-Barre is located, saw swings in margins of up to 25% toward Donald Trump, making him the first Republican candidate for president to carry Pennsylvania since George H. W. Bush in 1988. 2016 would also be the first presidential election in which Pennsylvania voted to the right of the nation since 1948. Pennsylvania's vote for Donald Trump marked the fall of the Democratic Blue Wall, a block of over 240 electoral votes that voted solidly Democratic from 1992 to 2012.

Pennsylvania had been one of the eleven states to vote twice for Bill Clinton in 1992 and 1996 which Hillary Clinton lost in 2016.